How do salamanders regenerate lost appendages?

Washington, July 30 (IANS) How do salamanders regenerate fingers even if they are sundered repeatedly is a question that has intrigued biologists. Besides the salamander, even sea squirt (Ciona intestinalis), a cylindrical creature as big as a tiny cucumber, loses its feeding tubes to hungry predators.

At the base of each siphon are eight photoreceptors to detect light. Whenever the squirt experiences their violent loss, it grows back an equal number of photoreceptors.

“The question I’m interested in is not only what mechanisms are involved in regeneration, but how exact (photoreceptor) patterns are formed,” said William R. Jeffery, professor of biology at the University of Maryland, who is investigating the phenomena.

Following up on previous research, in which he experimentally induced variations in the number of photoreceptors that regenerate by manipulating the siphon’s diametre, Jeffery will test the role of the Notch signalling pathway, a highly conserved molecular cascade that determines how an embryo forms.

If Jeffery is on the right track, not only will he develop a model of regeneration in sea squirts, but in salamanders as well. Basic research on animal regeneration is a foundation for a major goal in medicine: Learning how to guide human stem cells to regenerate new tissues or organs.